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Hi everyone,

I've spent the last few hours trying to figure out why my light fixture wouldn't turn on and I finally threw in the towel. So I just bought a home that has 2 adjoining light fixtures that are controlled by a switch. Thinking that it was the switch that was causing an open circuit, I replaced it but the lights still would not turn on. I've tried everything from using new bulbs to testing the sockets with a voltage tester. There is a voltage detected, but no light. Could the circuit be incorrect? I've never seen a 9 wire junction box before, only 3, with one hot, one neutral and one ground. Any advice on this would be appreciated.

  • Which wire is hot? And when voltage is detected is it only when you turn on the switch? Or always on?
    – Starboy
    Mar 4, 2017 at 6:25
  • Voltage is only detected at the socket where the bulb sits when the switch is turned on. Black wires are hot, and white are neutral (I think).
    – Bryce
    Mar 4, 2017 at 6:39

1 Answer 1


Assuming that box is wired correctly and to code, it looks like this would be true:

The lower right is the cable from the service (always energized). Its black is always-hot and its white is always-neutral. (all the neutrals are always-neutral; this setup properly switches the hot.)

The upper cable is the switch loop. The black wire is always-hot. Switched-hot comes back on the white wire, and that wire should be wrapped with some electrical tape to designate it as a hot. Historically that marking wasn't mandatory if the application was obvious; do you think it is obvious?

The black wire to the light fixture is switched-hot. The white wire to the lamp is neutral.

The lower left is the cable to the other light fixture. It is the same: black is switched-hot, white is neutral.

Equipment safety ground is all tied together, of course.

  • That is very useful information thank you. So you're saying that the circuit makes sense, and it should technically light the bulb, but in this case it still doesn't. I would still appreciate any thoughts on any other possible reasons why the bulb does not light up.
    – Bryce
    Mar 4, 2017 at 7:10
  • 1
    First confirm my/your hypothesis is correct, by confirming that there is in fact 120V across the lower right wires when the switch is off. Then it's one step at a time. Does the switched-hot light up when the switch is on? Does the lamp socket receive that power? Does the bulb work in other fixtures? One of these tests must surely fail, and then you know how to attack it. Mar 4, 2017 at 7:33

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